Game machines, such as a slot game machine and a pinball game machine, have been devised to perform presentation that arouses the player's visual sense, auditory sense, or feeling so as to enhance the player's interest. Especially for performing presentation that arouses the player's visual sense, a movable body, such as a movable accessory, may be provided in the game machine. A motor is used for driving such a movable body. For moving the movable body by a predetermined moving amount at a predetermined speed in accordance with the presentation, a motor control device is used, for example. The motor control device receives a control command including a target speed and a target rotation amount from an upper-level device, for example, and controls the motor in accordance with the command.
In order to enhance the player's interest, a large-sized movable accessory may be mounted in the game machine. Driving such a movable accessory requires a motor having high torque. There may thus be used a direct current (DC) motor that is cheaper than a stepping motor, and is smaller in size than the stepping motor to exert the same torque. In this case, along with the DC motor, a rotation angle sensor is used which outputs a detection signal in every rotation of the DC motor at a predetermined angle. The motor control device counts the number of times it has received a detection signal from the rotation angle sensor, and can thereby determine whether or not the moving amount of the movable body has reached the predetermined moving amount. When the moving amount reaches the predetermined moving amount, the motor control device stops the rotation of the DC motor.
A technique of using a Hall sensor provided in the motor as the rotation angle sensor has been proposed (e.g., see Japanese Patent Application No. 2011-87440). Further, a technique of using a rotary encoder as the rotation angle sensor has been proposed (e.g., see Japanese Patent Application No. 2014-73024).
For precisely detecting the position of the movable body that is driven by the motor, it is preferable to use the rotary encoder that can make angular resolving power relatively high. Meanwhile, since the rotary encoder has a disk-like component fitted to a rotary shaft of the motor, the use of the rotary encoder requires a relatively large space on a plane orthogonal to the rotary shaft of the motor. However, it may be difficult to ensure such a space, depending on the game machine. In such a case, as the rotation angle sensor, a Hall sensor built in the motor is preferably used.
As thus described, a preferable type of rotation angle sensor may vary depending on the device installed with the motor and the motor control device. Further, in recent years, the reuse of a substrate mounted with the motor control device has been considered. In this case, there can be a difference in type of rotation angle sensor to be used before and after the reuse. Hence, the motor control device is preferably usable with respect to a plurality of different types of rotation angle sensors.